Re: [asa] How big a deal is homology?

From: David Opderbeck <dopderbeck@gmail.com>
Date: Wed Mar 28 2007 - 12:55:13 EDT

*So, given that theology is neutral to progressive creation vs. creation by
evolution, then the answer is determined what does the non-theological
evidence point to and for that it is abundantly on the latter.*

Right -- if that "given" about theology is really "given." This is also
what I was trying to get at regarding Collins' evidence for evolution. I
don't think it's enough to make the scientific case. This also relates to
one of Iaian's comments about God of the gaps.

The scientific case is very clear: some gaps in the fossil record, some
gaps or inconsistencies in reconstructing genetic trees, a pretty big gap in
fully understanding all the mechanisms of evolution, an equally big gap in
understanding how life got started -- none of these suggest "God did it."
Science continues to look for natural explanations for those gaps and has a
pretty good track record in this regard. Evolution remains a firmly
established scientific theory and the best scientific explanation for how
life developed.

The larger epistemological case is not so clear, however, IMHO. Here I
think the ID and "theistic science" folks potentially have a valid point.
The average person isn't really interested in what "Science" says. The
average person is really interested in what is the Truth. What Science says
very well might not be the Truth given that Science must confine itself to
natural causes. Science itself, properly circumscribed, has to acknowledge
this.

A Christian who is convinced that his theology requires a God who separately
creates at least at the level of "kinds" is then empistemically justified in
rejecting Collins' evidence for "evolution" and instead placing it into a
framework of progressive creation. It is possible, and I would argue,
justifiable, to take such a stance without necessarily claiming that the
"gaps" in naturalistic explanations "require" or "prove" that there is a
God. Looked at this way, Collins' proofs aren't very compelling at all.
They're just a body of empirical data that can be interpreted differently in
accordance with different presuppositions.

IMHO, the deeper level of engagement is at the level of those
presuppositions. A progressive creationist who rejects TE will see the
distinctions between his position and TE start to vanish only if he becomes
convinced that good theology does *not* require distinct acts of
discontinuous separate creation. Such a person needs a thicker
understanding of the different ways in which God acts causally in nature.
He also needs a credible and consistent hermeneutic that accounts for the
critical questions of Adam, the image of God in humanity, and original sin.

On 3/28/07, Rich Blinne <rich.blinne@gmail.com> wrote:
>
>
>
> On 3/28/07, David Opderbeck <dopderbeck@gmail.com> wrote:
> >
> >
>
> Don't get me wrong, I appreciated Collins' book and admire him, and I'm
> very glad he's injecting some new ideas into the coversation and that
> publications such as Christianity Today are taking notice. But, I still
> think his book was seriously weakened by some of his broader jabs at ID. In
> many cases, the TE pointing a finger at ID has three fingers pointing back
> at himself. At some point, given an orthodox understanding of God's
> sovereignty, it seems to me that the distinction between "progressive
> creation" and "creation by evolution" becomes meaningless.
>
> So, given that theology is neutral to progressive creation vs. creation by
> evolution, then the answer is determined what does the non-theological
> evidence point to and for that it is abundantly on the latter. God COULD do
> either. The question is what DID God do. Your concern about gene to
> pseudogene transitions only deals with an edge condition of a larger issue
> which is known as copy number variation. Copy number variation is where
> parts of the genetic code get duplicated or deleted. The issues being
> currently pondered look like this question: If particular genes have a
> function then what is the "functional" difference when there exists copy
> number variation? While copy number variation is getting lots of play these
> days the idea has been around for quite a while. For example, during my
> literature search I found a paper on it dating from 1987.This phenomonon
> appears to make the genetic differences not only between between species but
> within species larger than originally appreciated. The concept of genes as
> "functional legos" that gets stacked differently from species to species by
> the progressive creationists is thus overly simplistic.
>
> For example,
>
>
> http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.0020207
>
>
> > Given that gene duplication is a major driving force of evolutionary
> > change and the key mechanism underlying the emergence of new genes and
> > biological processes, this study sought to use a novel genome-wide approach
> > to identify genes that have undergone lineage-specific duplications or
> > contractions [RDB note: these contractions are apparently what bothers
> > David.] among several hominoid lineages. Interspecies cDNA array-based
> > comparative genomic hybridization was used to individually compare copy
> > number variation for 39,711 cDNAs, representing 29,619 human genes, across
> > five hominoid species, including human. We identified 1,005 genes, either as
> > isolated genes or in clusters positionally biased toward rearrangement-prone
> > genomic regions, that produced relative hybridization signals unique to one
> > or more of the hominoid lineages. Measured as a function of the evolutionary
> > age of each lineage, genes showing copy number expansions were most
> > pronounced in human (134) and include a number of genes thought to be
> > involved in the structure and function of the brain. This work represents,
> > to our knowledge, the first genome-wide gene-based survey of gene
> > duplication across hominoid species. The genes identified here likely
> > represent a significant majority of the major gene copy number changes that
> > have occurred over the past 15 million years of human and great ape
> > evolution and are likely to underlie some of the key phenotypic
> > characteristics that distinguish these species.
> >
>
> See here for both positive and negative copy number variation amongst the
> different great ape species:
>
> http://biology.plosjournals.org/perlserv/?request=slideshow&type=figure&doi=10.1371/journal.pbio.0020207&id=9002
>
>
>
>

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Received on Wed Mar 28 12:55:51 2007

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